Lead C#/.NET Engineer for Mission-Critical Benefits System

Dew Softech Inc; Trenton (NJ); On-site; USD 110,000 - 150,000; Full time

Job summary

Dew Softech Inc in Hamilton, NJ seeks a Sr/Lead C#/.NET Engineer to lead modernization of a mission-critical benefits system hosted on AWS. This full-time, on-site role requires deep expertise in C#, EF Core, and relational databases, and will own the data-access architecture against PostgreSQL.

You will mentor developers, set coding standards, and ensure functional equivalence with the legacy COBOL/JCL system while delivering high-performance, production-grade code within the nightly batch

Qualifications

• 12–15 years of professional C#/.NET software engineering, including senior/lead responsibilities.
• Deep expertise in C# and the .NET platform (.NET Framework and .NET Core / .NET 6/8+), including async programming, memory/performance optimization, and modern language features
• Expert-level Entity Framework / EF Core: entity modeling, Fluent API, migrations, query optimization, transactions, concurrency, provider-specific behavior
• Strong relational database skills; PostgreSQL strongly preferred (Oracle/SQL Server acceptable) schema design, indexing, query tuning, stored procedures
• ASP.NET Core Web API design (REST) for front-end integration
• Solid software design: SOLID, design patterns, domain modeling, layered/clean architecture, dependency injection
• Testing discipline: unit/integration/regression testing frameworks; TDD/mocking
• Git, CI/CD, and static code analysis (SonarQube)
• Proven ability to read, reason about, and safely refactor large, unfamiliar codebases
• Exceptional attention to correctness financial/benefit calculation accuracy

Responsibilities

• Refactor machine-converted, COBOL-derived C# into idiomatic, maintainable .NET meaningful naming, proper OO/domain design, separation of concerns, dependency injection
• Work in .NET (Core) / .NET (latest version); apply modern C# language features (LINQ, async/await, records, pattern matching, nullable reference types, generics)
• Design and implement service layers, domain models, and APIs (ASP.NET Core Web API) that back the Angular UI
• Refactor legacy batch/procedural logic (converted from COBOL/JCL) into maintainable, testable .NET; handle exact decimal/financial arithmetic to preserve benefit-calculation correctness
• Optimize performance to meet the nightly batch window (profiling, memory management, async I/O, parallelism where safe)
• Own the data-access architecture using EF Core against PostgreSQL (Npgsql provider)
• Refactor the auto-generated/converted data-access layer into a clean, performant EF Core model
• Design entity models, DbContext configuration, Fluent API mappings, relationships, keys, and indexes reflecting the IDS-II PostgreSQL schema
• Optimize EF Core queries (eager/lazy/explicit loading, projection, AsNoTracking, compiled queries, batching) to avoid N+1 and meet performance SLAs on high-volume batch operations
• Manage EF Core migrations, concurrency handling, transactions, and connection resiliency
• Map legacy data types and semantics correctly to PostgreSQL/EF types without behavioral drift
• Contribute to the COBOL-field PostgreSQL-column business-term data dictionary
• Define and enforce C#/.NET coding standards, architecture patterns, and refactoring guidelines for the engineering team
• Serve as senior technical authority on the converted codebase; make cross-cutting design decisions
• Mentor mid/junior C# developers; perform code reviews; drive engineering quality
• Partner with the Technical Manager/Architect on target architecture and the refactoring strategy
• Ensure functional equivalence: build unit and regression tests to validate refactored code against the legacy baseline; fix defects
• Integrate with CI/CD (AWS CodeBuild/CodePipeline), enforce gates (SonarQube, static analysis, secure coding)
• Collaborate with FAMIS SMEs to preserve business logic (eligibility, benefit calculation, payments, EBT)
• Deliver incrementally within Scrum; document design and decisions

Skills

C#

.NET

EF Core

PostgreSQL

ASP.NET Core

AWS

Performance optimization

Tools

Entity Framework Core (EF Core)

PostgreSQL

ASP.NET Core Web API

AWS (CodeBuild/CodePipeline)

Job description

Dew Softech Inc in Hamilton, NJ seeks a Sr/Lead C#/.NET Engineer to lead modernization of a mission-critical benefits system hosted on AWS. This full-time, on-site role requires deep expertise in C#, EF Core, and relational databases, and will own the data-access architecture against PostgreSQL.

You will mentor developers, set coding standards, and ensure functional equivalence with the legacy COBOL/JCL system while delivering high-performance, production-grade code within the nightly batch